Air Conditioning, Humidification, Postoperative Complications, Pulmonary Complications in Surgical Patients, Video Assisted Thoracic Surgery (VATS)
Conditions
Keywords
VATS, Postoperative complications, Humidification, Thoracic Surgery, Pulmonary Complications, One-Lung Ventilation, Heat and Moisture Exchanger, HME, Air Conditioning
Brief summary
General anesthesia with endotracheal intubation bypasses the physiological warming and humidification functions of the upper airway, allowing cold and dry gases to reach the lower respiratory tract. This may impair mucociliary clearance, increase secretion viscosity, promote atelectasis, and contribute to postoperative pulmonary complications (PPCs). Patients undergoing thoracic surgery, particularly those requiring one-lung ventilation (OLV), are at increased risk for PPCs because of altered ventilation-perfusion matching, reduced functional residual capacity, and impaired secretion clearance. Although respiratory gas humidification is routinely used during anesthesia, evidence regarding the comparative clinical effects of active heated humidification (AHH) and passive heat and moisture exchangers (HMEs) during thoracic surgery remains limited. This prospective observational cohort study aims to evaluate the association between intraoperative respiratory gas humidification methods and postoperative pulmonary complications and perioperative clinical outcomes in adult patients undergoing elective video-assisted thoracoscopic surgery (VATS).
Detailed description
The physiological conditioning of inspired gases is bypassed during general anesthesia with endotracheal intubation. Delivery of inadequately heated and humidified gases to the lower respiratory tract may impair mucociliary function, increase secretion viscosity, reduce airway patency, and promote postoperative pulmonary complications. Patients undergoing video-assisted thoracoscopic surgery (VATS) frequently require one-lung ventilation, which further increases susceptibility to pulmonary complications through ventilation-perfusion mismatch, impaired secretion clearance, and atelectasis formation. Two principal approaches are used for intraoperative respiratory gas conditioning: Passive heat and moisture exchangers (HMEs) Active heated humidification systems (AHHs) Although HMEs are widely used because of their simplicity, they may provide insufficient humidification during prolonged procedures, high minute ventilation, or one-lung ventilation. Active heated humidifiers deliver gases closer to physiological conditions (approximately 37°C and 100% relative humidity), potentially reducing secretion viscosity and improving airway patency. Most existing studies evaluating respiratory gas humidification have focused on intensive care patients receiving prolonged mechanical ventilation. Evidence regarding thoracic surgical patients remains limited, particularly during one-lung ventilation. This prospective, single-center observational cohort study will compare perioperative outcomes among patients managed with active or passive humidification according to routine anesthetic practice. No intervention or randomization will be performed.
Interventions
DEVICEActive Heated Humidification
An active heated humidification system integrated into the anesthesia breathing circuit is used during intraoperative mechanical ventilation to warm and humidify inspired respiratory gases. Device selection and clinical management are determined solely by the attending anesthesiologist according to institutional routine practice. No study-specific intervention or modification of patient care is performed.
A passive heat and moisture exchanger filter is incorporated into the anesthesia breathing circuit during intraoperative mechanical ventilation to conserve heat and moisture from exhaled gases. Device selection is based on routine clinical practice, and no intervention is assigned by the study protocol.
Sponsors
Marmara University
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
18 Years to 75 Years
Healthy volunteers
No
Inclusion criteria
* Patients aged 18 to 75 years * Elective video-assisted thoracoscopic surgery (VATS) * Lung resection requiring general anesthesia * Planned one-lung ventilation * Written informed consent
Exclusion criteria
* Emergency surgery * Pregnancy * Preoperative mechanical ventilation * Previous enrollment * Refusal to participate
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Incidence of Postoperative Pulmonary Complications | From completion of surgery through postoperative Day 7. | Incidence of one or more postoperative pulmonary complications occurring within 7 days after surgery, including atelectasis, pneumonia, secretion retention, bronchoscopy for mucus plugging, prolonged oxygen requirement, requirement for non-invasive or invasive ventilatory support, or reintubation. PPCs will be assessed using predefined clinical and radiological criteria. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Oxygenation (PaO₂/FiO₂ Ratio) | Measured during one-lung ventilation and at the end of surgery. | Intraoperative arterial oxygenation assessed by the ratio of arterial oxygen partial pressure (PaO₂) to the fraction of inspired oxygen (FiO₂). |
| Frequency of Endotracheal Suctioning | From induction of anesthesia until completion of surgery. | Number of endotracheal suctioning procedures performed during the intraoperative period. |
| Airway Secretion Viscosity Score | During one-lung ventilation, at the end of one-lung ventilation, and within 24 hours after extubation. | Airway secretion viscosity assessed using a semi-quantitative 5-point scale (0 = no secretions, 1 = watery secretions, 2 = mildly viscous secretions, 3 = thick secretions difficult to aspirate, 4 = very thick obstructive secretions). The highest score recorded for each patient will be used for analysis. |
| Incidence of Intraoperative Hypothermia | From induction of anesthesia until completion of surgery. | Proportion of patients developing intraoperative hypothermia, defined as a core body temperature \<36.0°C. |
| Incidence of Postoperative Hypothermia | Within the first 24 hours after surgery. | Proportion of patients with body temperature \<36.0°C during postoperative monitoring. |
| Postoperative Oxygen Therapy Requirement | Within the first 72 hours after surgery. | Requirement for supplemental oxygen after surgery. |
| Requirement for Non-invasive Ventilation | Within the first 72 hours after surgery. | Requirement for postoperative non-invasive ventilatory support. |
| Intensive Care Unit Length of Stay | From ICU admission until ICU discharge, up to postoperative Day 30. | Duration of admission to the intensive care unit. |
| Hospital Length of Stay | From surgery until hospital discharge, up to postoperative Day 30. | Length of hospitalization measured from the date of surgery until hospital discharge. |
| Bronchodilator Therapy Requirement | Within 7 days after surgery. | Proportion of patients requiring bronchodilator treatment during the postoperative period. |
| C-Reactive Protein (CRP) | Postoperative Day 7. | Serum C-reactive protein concentration as a marker of postoperative inflammatory response. |
Countries
Turkey (Türkiye)
Contacts
CONTACTNezaket Nur Arslan Kömür, MD
CONTACTSeniyye Ülgen Zengin, Associate Professor, MD
STUDY_CHAIRNezaket Nur Arslan Kömür, MD
Marmara University
PRINCIPAL_INVESTIGATORSeniyye Ülgen Zengin, Associate Professor
Marmara University
STUDY_DIRECTORMeliha Orhon Ergün, Associate Professor, MD
Marmara University
Outcome results
None listed